Chicago, Burlington & Quincy 4-6-4 "Hudson" Locomotives in the USA

The Chicago, Burlington & Quincy Railroad purchased twelve Hudsons from the Baldwin Locomotive Works in 1930. These 4-6-4's were designated Class S-4 and assigned road numbers 3000 through 3011. The CB&Q also built two Hudsons in its own shops and assigned them road numbers 3012 and 4001. There are four surviving CB&Q Hudsons and they are on display at locations in Iowa, Illinois and Wisconsin.

Class Details by Steve Llanso of Sweat House Media

Class S-4 (Locobase 181)

Data from Corbin & Kerka (1960); "4-6-4 and 4-8-4 Type Power for the CB&Q", Railway Age, Volume 90, No 10 (7 March 1931), pp. 499-500; and locomotive diagram published on Vernon Beck's website -- [] (accessed 22 March 2003) CB&Q 3 - 1953 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. (Thanks to Chris Hohl for pointing out the error in renumbering for the second Zephyr-style streamliner; and for his 22 September 2017 email reporting unlikely boiler pressure values for 177 entries. A Locobase macro caused the error.) See also DeGolyer, Volume 81, pp. 329+. Works numbers were 61445-61446 in August 1930, 61500-61501 in September, 61525-61528 in October, and 61555-61558 in November.

Twelve by Baldwin, a thirteenth (S-4A) by the West Burlington shops using a Baldwin boiler. All but 4001 had Elesco feedwater heaters; 4001 had a Worthington. The engine bed was cast intergrally with the cylinders. Other goodies included a Barco Type 4 power reverse gear, Franklin trailing truck boosters, Type B stokers, and 14" (356 mm) diameter pistons. Firebox heating surface included 43 sq ft (4.0 sq m) of arch tubes and 70 sq ft (6.5 sq m) of combustion chamber.

Corbin & Kerka wrote that when these locomotives went into service pulling such trains as the Ak-Sar-Ben, the Aristocrat, and the Black Hawk, the Burlington was able to do away with swapping one locomotive for another during the trip. One is credited with hauling ten standard passenger cars between Cochrane and La Crosse (Wis) at 112 mph (180 kph). The authors conclude "The 4-6-4 types were perhaps the some of the most successful locomotives used on the Chicago, Burlington & Quincy."

One (3002) was streamlined to resemble the stainless-steel Zephyrs, renumbered 4000 and called Aeolus and nicknamed "Big Alice the Goon." After her success, a second was built from scratch and numbered 4001.

The modification, dubbed S-4A, was more than cosmetic. The pair also received Box-Pok drivers and roller bearings in the lightweight side rods. Three more S-4s (3008, 3009, and 3011) received the running gear upgrades in 1938, but not the shrouds. They were renumbered 4003-4005.

Principal Dimensions by Steve Llanso of Sweat House Media
Locobase ID181
RailroadChicago, Burlington & Quincy (CB&Q)
Number in Class12
Road Numbers3000-3012
Number Built12
Valve GearBaker
Locomotive Length and Weight
Driver Wheelbase (ft / m)13.67 / 4.17
Engine Wheelbase (ft / m)39.92 / 12.17
Ratio of driving wheelbase to overall engine wheebase 0.34
Overall Wheelbase (engine & tender) (ft / m)82.23 / 25.06
Axle Loading (Maximum Weight per Axle) (lbs / kg)69,780 / 31,652
Weight on Drivers (lbs / kg)207,730 / 94,225
Engine Weight (lbs / kg)391,880 / 177,754
Tender Loaded Weight (lbs / kg)326,050 / 147,894
Total Engine and Tender Weight (lbs / kg)717,930 / 325,648
Tender Water Capacity (gals / ML)15,000 / 56.82
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)24 / 21.80
Minimum weight of rail (calculated) (lb/yd / kg/m)115 / 57.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)78 / 1981
Boiler Pressure (psi / kPa)250 / 17.20
High Pressure Cylinders (dia x stroke) (in / mm)25" x 28" / 635x711
Tractive Effort (lbs / kg)47,676 / 21625.50
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.36
Heating Ability
Firebox Area (sq ft / m2)369 / 34.29
Grate Area (sq ft / m2)87.90 / 8.17
Evaporative Heating Surface (sq ft / m2)4247 / 394.70
Superheating Surface (sq ft / m2)1830 / 170.07
Combined Heating Surface (sq ft / m2)6077 / 564.77
Evaporative Heating Surface/Cylinder Volume266.97
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation21,975
Same as above plus superheater percentage28,568
Same as above but substitute firebox area for grate area119,925
Power L146,094
Power MT1467.57

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Wes Barris